Cylinder for internal-combustion engines.



, H. IUNKERS. CYLINDER FOR INTERNAL COMBUSTION ENGINES. APPLICATION FILED FEB. I9. I916.

11,31,94 Patented July 3, 1917.

- subject of the Emperor HUGO JUNKERS, OF AAGHEN, GERMANY.

CYLINDER FOR INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent.

' Patented July 3, 19117..

Original application filed June 25, 1913, Serial No. 775,693. Divided and this application filed February 19,

, 1916. Serial No. 79,242.

To all whom it may concern:

Be it known that I, HUGO JUNKERs, a

of Germany, residing in Aachen, Germany, have invented certain'new and useful Improvements in Cylinders for Internal-Combustion Engines; and I do hereby declare the' following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This inventionis directed to the provision of an improved construction for the cylinders of internal combustion engines and constitutes a division of an application filed by me on June 25, 1913, Serial No. 775,693.

The cylinder of an internal combustion engine must be capable of withstanding intense internal pressure and also it is necessary that the heat absorbed by the cylinder walls be carried away efliciently. The former of these two considerations suggests increase of the thickness of the cylinder walls but that increases the dih'iculty of carrying away the heat and at the same time increases the detrimental effect of uneven expansion and contraction of the metal of the cylinder walls under different degrees of heat. The present invention involves the provision of an improved construction for such a cylinder whereby ample strength to withstand the internal pressure is provided, whereby the cooling medium is carried close to the interior wall of the cylinder so that it is made the more effective in conducting away heat and whereby the wall of the cylinder may be made so thin as to minimize the effect of unequal "expansion and contrac-' tion therein.

In accordance with the invention, I employ an inner cylinder or liner, the walls of which are relatively thin, this liner possessing insufficient strength in itself to withstand the strains to which it is subjected when the engine is in operation. To such a liner'I apply a plurality of separate rings which are placed upon the liner by forcing or shrinking them thereon. These rings possess a high degree of strength and they take up the strains to which the liner is subjected so as to preventdistortion "of the latter. These rings are spaced apart in the direction of the axis of the cylinder so that between them are ample spaces into which a cooling medium may enter so as to come in contact with the exterior wall of the liner and absorb heat therefrom. In order to form a suitable chamber foithe reception of the coohng medium, an outer jacket is provided surrounding the liner and rings. This jacket'merely retains the cooling liquid and does not perform any function in strengthenlng the cylinder structure; it may contact with the exterior surfaces of the rings or be spaced apart therefrom as desired, the latter construction being preferred.

A cylinder constructed in this manner possesses several advantageous characteristics. It may be made of ample strength as its capacity for withstanding the internal strains is limited only by the strength of the rings applied to the liner and these may be made of such material and dimensions as will afford the requisite degree of strength. Between the rings are spaces for a cooling liquid which liquid comes in contact with the exterior surface of the thin liner over the entire surface of the liner not covered by the rings so that the cooling medium is carried close to the interior wall of the cylinder. The area of the liner with which the cooling medium contacts may be increased if desired by suitably forming the interior surfaces of the rings without detracting from the strength .of the rings. Moreover, the use of rings formed separate from the liner and thereafter applied thereto by driving them on theliner or shrinking them thereon, permits of spacing the rings along the length of the cylinder in the manner desired, as for instance, by arranging the rings closer together over a portion of the cylinder, which, during the operation of the engine is subjected to the greatest internal strain. Furthermore, this form of cylinder construction conduces toward low cost of manufacture as the provision of the rings and liner of the desired dimensions and'the assemblage of these parts may be readily accomplished.

I have illustrated the preferred embodiment of my invention in the accompanying drawing, in which the figure is a longitudinal section of a portion of a. cylinder for an internal combustion engine.

Referring to the drawing, 1 indicates the liner within which the piston of the engine reciprocates. The liner may be of uniform section throughout and the wall thereof is relatively thin, so much so that this liner in itself has insufficient strength to withstand the pressure of the gases admitted thereto. The strength necessary in the cylinder structure is provided by a plurality of rings 2 which closely encircle the liner 1, these several rings being spaced apart in the direction of the length of the. cylinder as is indicated in the drawing. The rings make a tight fit upon the liner so that the internal strains are transmitted directly from the liner to the rings and distortion of the liner is effectually guarded against. If desired, the rings may be of such size as to make a driving fit upon the liner and. they are forced into their positions thereon. Or, the rings may be heated to expand them sulficient to permit of positioning them upon the liner and thereafter shrunk so as to make them fit tightly upon the liner. Between the several rings 2 are ample spaces for accoling liquid, which liquid comes in contact with the exterior wall of the liner 1 throughout thevspaces between the rings. If desired, the area of the liner with which the cooling medium contacts may be increased substantially without appreciably reducing the strength of the rings2 by cutting away the material of the rings along the interior edges thereof, as is indicated in the drawing where the rings are shown as of trapezoidal cross-section. In the drawing, the liner 1 is shown as provided with seats for the rings 2, which seats are slightly raised, but if desired, the liner may be of uniform thickness throughout.

Surrounding the liner 1 and rings 2 is a jacket or casing 3 which forms with the liner a receptacle for the cooling medium. This casing 3 may be formed of thin sheet metal such as tin or copper. This casing 8 is not subjected to the pressure which is gen erated within the liner 1; as shown in Fig. 1, the liner is spaced from the rings 2, though if desired, it may be in contact with the outer surfaces of the rings, in which latter case provision is preferably made for passage of the cooling liquid lengthwise of the cylinder past the several rings.

With this construction, ample strength to withstand the internal pressure is secured while still having the cylindrical wall Within which the piston reciproc'ates of such relatively small thickness as to permit of carrying the cooling liquid in close proximity to the interior wall of the cylinder. As a result, heat absorbed by the cylinder wall is carried away efliciently and the detrimental effects of unequal expansion and contraction within the cylinder wall is materially reduced. By forming the rings separately from the liner and thereafter applying them thereto, the cost of construction is greatly reduced and materials which are best suited for use in these different parts may be employed. Furthermore, the rings may be spaced apart in such manner as is found to be desired in order to reinforce the liner to a greater extent over a portion thereof which is subjected to a greater strain.

What I claim is:

1. A cylinder for an internal combustion engine comprising a cylindrical liner of insuflicient thickness to provide the strength necessary to withstand the internal pressure, a plurality of separate rings closely encircling the liner to receive the strain transmitted to them by the liner and prevent distortion of the liner, and a casing separate from the rings and forming with the liner and rings a chamber for a cooling medium, the rings being spaced apart lengthwise of the cylinder to permit the cooling medium to contact with the exterior wall of the liner between adjacent rings; substantially as described.

2. A cylinder for an internal combustion engine comprising a liner, a plurality of separate rings closely encircling the liner, and a casing separate from the rings and forming with the liner and rings a chamber for a cooling medium, the several rings being spaced apart to permit the cooling medium to enter between them, and the area of contact of the cooling medium with the exterior wall of the liner being increased by reducing the width of the rings at the interior thereof, substantially as described.

In testimony whereof I affix my signature.

HUGO J UNKERS. 

